Preheat the broiler and line a rimmed baking sheet with foil.
Season the meat with the salt and pepper. In a large skillet over low heat, combine the vinegar, brown sugar, garlic, and bay leaf. Simmer until the liquid has reduced by half and is a syrupy consistency, about 5 minutes. Discard the garlic and bay leaf.
Put the meat on the baking sheet and slather it with the glaze. Broil the meat 4 inches from the heat until it reaches the desired level of doneness, about 4 to 5 minutes per side. Remove from the broiler to a cutting board and let rest for 5 minutes. Thinly slice the meat against the grain and transfer it to a serving platter.
When using the broiler, crack the oven door open so the meat does not burn.